LoL it's not too late don't worry.It's a simple Windows file that is missing.
I have uploaded that file for you from my computer.Download it from here:
http://www.sendspace.com/file/fnz0yp
Now save that "shell32.dll" file to some external device such as USB stick.
Now also download Ubuntu 9.04 DESKTOP CD x86 from here:
http://old-releases.ubuntu.com/releases/9.04/
Now do the following:
-plug the USB stick on which you have put "shell32.dll" file into that computer which is giving you an error
-Burn that UBUNTU ISO file on a blank CD disk
-put that CD disk in that computer on which you are getting that error
-go into BIOS and make sure that the CD/DVD-ROM drive is set as the first device to boot from
-save changes and restart
-Ubuntu CD disk will now boot
-Choose ENGLISH language
-Choose first option called "Try Ubuntu without any change to your computer"
-Ubuntu will now start loading from the CD disk so do NOT touch your CD/DVD-ROM or you computer now
-once you see the desktop,at the top go to PLACE--->COMPUTER
-now on the window,go to VIEW and click SHOW HIDDEN FILES
-now go into your USB stick and from there copy that file called "shell32.dll"
-go back
-now go into your hard disk drive and then go on the following location:
WINDOWS\system32\
-once you are in the "system32" folder,simply paste that "shell32.dll" file there
-close the window
-at the top on the right click LIVE SESSION USER and then click SHUT DOWN
-click SHUT DOWN again on the small window that has just opened
-Ubuntu will start shutting down
-once the Ubuntu is shutted down,the CD will be ejected automatically
-take the CD out,close the tray of the CD drive and click ENTER
-after the computer has turned off,wait for 15 seconds at least
-turn on your computer now and TADA!You are done...
Cheers!